Floor Reference Voltage Control for Power Supply Startup
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Solution Overview
Problem
Conventional power supplies face performance issues during startup and discontinuous conduction modes due to the slow response of floor voltage amplifiers, leading to non-linear and protracted startup processes, high converter currents, and unpredictable output voltage ripple.
Innovation Solution
A power supply system that includes a floor reference voltage generator, mode controller, and phase control circuitry, allowing switching between fixed and variable floor reference voltage modes to improve output voltage regulation across different operational conditions, using a ramp generator to form an offset ramp voltage signal and a comparator to activate switch circuitry based on feedback signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a floor voltage amplifier is used to regulate output voltage, then voltage regulation accuracy is improved, but response time during startup becomes excessively slow
Solution Approach 1:
The system dynamically switches between two operational modes: a first mode during startup where the floor reference voltage is disabled to allow fast response, and a second mode during steady-state operation where the floor reference voltage is enabled to provide accurate regulation. This dynamic switching resolves the contradiction by having different control strategies for different operational phases.
Solution Approach 2:
The system performs preliminary action by disabling the floor reference voltage during startup before switching it on during steady-state operation. This preliminary configuration allows the system to avoid the slow response issue during startup while still benefiting from accurate regulation during normal operation.
2Measurement precision
If a floor voltage amplifier is used to improve voltage regulation, then output voltage accuracy is improved, but converter current increases during startup
Solution Approach 1:
The system dynamically controls the floor reference voltage based on operational mode, disabling it during startup to reduce converter current and enabling it during steady-state to improve voltage accuracy. This dynamic control resolves the contradiction between current consumption and voltage accuracy.
3Device complexity
If conventional voltage regulation is used, then circuit simplicity is maintained, but output voltage ripple becomes unpredictable during discontinuous conduction modes
Solution Approach 1:
The system preliminarily disables the floor reference voltage during discontinuous conduction modes (detected by monitoring inductor current), preventing unpredictable voltage ripple while maintaining circuit simplicity. This preliminary action avoids the need for complex additional circuitry to handle discontinuous modes.
4Measurement precision
If floor reference voltage is used during startup, then voltage regulation is improved, but startup time becomes excessively long
Solution Approach 1:
The system dynamically switches the floor reference voltage on and off based on operational mode, using it only during steady-state operation and disabling it during startup. This dynamic switching resolves the contradiction by having the floor reference voltage active only when it provides benefit, avoiding startup time extension.
Data Source
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AI summary
A power supply includes a power converter, a reference voltage generator, and a controller. During operation, the power converter produces an output voltage to power a load. The reference voltage generator (such as a voltage mode amplifier circuit) generates a floor reference voltage, a magnitude of which varies as a function of the output voltage error. The controller compares an output voltage feedback signal (derived from the output voltage) to the floor reference voltage to produce control output to control timing of activating switches in the power converter to maintain the output voltage within a desired voltage range.